1. Field of the Invention
The present invention relates to an injection stretch blow container having a high gas-barrier quality due to the laminar structure of the blend of a saturated polyester and a saponification product of an ethylene-vinyl acetate copolymer (hereinafter referred to as "EVOH").
2. Description of the Prior Art
With respect to a composition of saturated polyester and EVOH, Japanese Laid-Open Pat. No. 20073/1981 discloses one of such composition, Japanese Laid-Open Pat. No. 76325/1985 discloses a biaxially stretched molded product, and Japanese Laid-Open Pat. No. 148442/1985 discloses a blown bottle.
When containers are produced by the methods disclosed in the above referenced Japanese patents, the gas barrier quality is improved if the amount of EVOH is less than about 30 wt %, but the degree of improvement is too low to be satisfactory in terms of enhancement of the preservability of foodstuffs. On the other hand, if the amount of EVOH is increased in order to improve the preservability, the moldability in during stretch blowing is reduced. Thus, it is difficult to produce the intended gas-barrier container. For these reasons, a container made of a composition of saturated polyester and an EVOH has not yet been put to practical use. It is known that a container having a high gas-barrier quality is obtained by laminating saturated polyester and an EVOH employing a co-extrusion technique, but this method has not been put to practical use either because of the high molding cost.